From the U.S. Pat. No. 6,217,448 B1, a system of linked gaming machines is known that is connected to an external controller and an overhead display. In a special bonus mode time period, the controller randomly determines one or more of the active gaming machines for bonus multiplier opportunities, where an award normally granted by a gaming machine is multiplied by a bonus multiplier. Upon a selected gaming machine obtaining a winning symbol combination, the gaming machine's internal control unit pays out the normal award, and the controller then causes the internal control unit to pay out the multiplied award. The increased payouts are deducted from a bonus pool.